1801805 has 8 divisors (see below), whose sum is σ = 2187000. Its totient is φ = 1424896.

The previous prime is 1801781. The next prime is 1801817. The reversal of 1801805 is 5081081.

It can be written as a sum of positive squares in 4 ways, for example, as 841 + 1800964 = 29^2 + 1342^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1801805 - 2⁸ = 1801549 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1580 + ... + 2469.

It is an arithmetic number, because the mean of its divisors is an integer number (273375).

2^1801805 is an apocalyptic number.

It is an amenable number.

1801805 is a deficient number, since it is larger than the sum of its proper divisors (385195).

1801805 is an equidigital number, since it uses as much as digits as its factorization.

1801805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4143.

The product of its (nonzero) digits is 320, while the sum is 23.

The square root of 1801805 is about 1342.3133017295. The cubic root of 1801805 is about 121.6846869745.

Adding to 1801805 its reverse (5081081), we get a palindrome (6882886).

It can be divided in two parts, 180 and 1805, that multiplied together give a square (324900 = 570²).

The spelling of 1801805 in words is "one million, eight hundred one thousand, eight hundred five".